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Templated Features Layer

In this section, we will learn how to create a templated feature layer. A templated feature layer is a layer that fetches a single .mapml file on pans and zooms.

Adding a templated feature layer​

<layer- label="Alabama" checked>
  <map-meta name="zoom" content="min=2,max=5"></map-meta>
  <map-extent units="CBMTILE" checked hidden>
    <map-input name="z" type="zoom" min="2" max="18" value="0"></map-input>
    <map-input name="xmin" type="location" units="gcrs" axis="longitude" position="top-left" min="-76" max="-74"></map-input>
    <map-input name="ymin" type="location" units="gcrs" axis="latitude" position="bottom-right" min="45" max="46"></map-input>
    <map-input name="xmax" type="location" units="gcrs" axis="longitude" position="bottom-right" min="-76" max="-74"></map-input>
    <map-input name="ymax" type="location" units="gcrs" axis="latitude" position="top-left" min="45" max="46"></map-input>
    <map-link rel="features" tref="data/alabama_feature.mapml?{xmin}{ymin}{xmax}{ymax}{z}"></map-link>
  </map-extent>
</layer->

Associated Elements​

<map-extent>​

  • units
    • This allows you to define what the projection of the templated features.

<map-input>​

  • axis

    • This attribute is only useful on inputs of type location, it sets the axis the following input defines. This value also defines what the min and max value's units.
    • Options are, row | column | easting | northing | latitude | longitude

  • name

    • This allows you to name the input, this name is then used in the url template used in the <map-link> href attribute.

  • type

    • Sets the type of the input.
    • Options are, zoom | location

  • max

    • Sets the maximum of the bounds of the layer on the given axis.

  • min

    • Sets the minimum of the bounds of the layer on the given axis.

  • position

    • Sets the position of the input, this can either be top-left or bottom-right.

  • value

    • Sets the zoom level the inputs of type location's min and max are defined at.

  • rel

    • Set this to features in the case of a templated features layer.

  • title

    • Sets the title of the layer, this is the title shown in the layer controls.

  • type

    • Sets the type of the returned data.

  • tref

    • Sets the templated url of the templated tile layer, this must contain all the names of the inputs used to query a given tile.

Additional Context​

You can also provide a set of elements to further define the templated feature layer. This is the list of available additions with examples.

<map-meta name="zoom">​

Sets the zoom range of the layer. The layer will make requests from zoom levels 1 to 5 in the example below.

<map-meta name="zoom" content="min=1,max=5"></map-meta>

Full Examples​

<mapml-viewer projection="CBMTILE" zoom="3" lat="45.5052040" lon="-75.2202344" controls>
  <layer- label="Alabama" checked>
    <map-meta name="zoom" content="min=2,max=5"></map-meta>
    <map-extent units="CBMTILE" checked hidden>
      <map-input name="z" type="zoom" min="2" max="18" value="0"></map-input>
      <map-input name="xmin" type="location" units="gcrs" axis="longitude" position="top-left" min="-76" max="-74"></map-input>
      <map-input name="ymin" type="location" units="gcrs" axis="latitude" position="bottom-right" min="45" max="46"></map-input>
      <map-input name="xmax" type="location" units="gcrs" axis="longitude" position="bottom-right" min="-76" max="-74"></map-input>
      <map-input name="ymax" type="location" units="gcrs" axis="latitude" position="top-left" min="45" max="46"></map-input>
      <map-link rel="features" tref="data/alabama_feature.mapml?{xmin}{ymin}{xmax}{ymax}{z}"></map-link>
    </map-extent>
  </layer->
</mapml-viewer>

[ADD MAP HERE]